KR101342365B1 - Method of transferring data in wireless communication system - Google Patents

Abstract

The present invention relates to a data transfer method in a wireless communication system. A data transfer method according to the present invention is a data transfer method for multiplexing a plurality of higher layer channels at a transmitting side of a wireless communication system and mapping them to a lower layer channel. And changing a predetermined priority for the at least one condition according to whether or not at least one condition is satisfied, and multiplexing each of the upper layer channel data by the amount determined according to the changed priority to the lower layer channel. Can be configured.

E-UMTS, LTE, Priority, TFC, TFCS

Description

Method of transferring data in wireless communication system

1 is a diagram illustrating a network structure of an E-UMTS.

2 is a schematic diagram of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN).

3A and 3B illustrate a structure of a radio interface protocol between a UE and an E-UTRAN. FIG. 3A is a control plane protocol diagram and FIG. 3B is a user plane protocol diagram .

4 is a process flow diagram of one preferred embodiment of the present invention.

FIG. 5 is a diagram illustrating a case of changing the priority based on the amount of data stored in the transmission buffer according to an embodiment of the present invention.

FIG. 6 is a diagram for describing a priority change method when the priority change of each service is performed based on an average waiting time of data in a transmission buffer according to one embodiment of the present invention.

7 to 9 are diagrams for explaining a process of selecting a specific TFC in the TFCS received from the network by the MAC layer of the terminal according to an embodiment of the present invention.

The present invention relates to a wireless communication system, and more particularly, to a data transfer method in a wireless communication system.

Recently, the necessity of providing a multimedia service such as an email service, a video communication service, an Internet service, etc. as well as a voice communication service is increasing day by day. Accordingly, a plurality of services are frequently transmitted at the same time through downlink or uplink.

In the case of multiplexing and transmitting a plurality of services, it is very important to determine how many radio resources are allocated and transmit each service according to which criteria. In general, a method of determining a priority for each service according to a type of service, a billing system, and the like and allocating radio resources according to the determined priority is frequently used.

The method of allocating radio resources according to priority has a problem in that quality of service (QoS) can be ignored. For example, in the case of transmitting a plurality of services having a difference in priority, if data for a high priority service is continuously generated, radio resources may be continuously allocated to the high priority service according to the priority. As a result, a low-priority service may not be able to meet the minimum quality of service required for the service because it has not been allocated radio resources for a long time.

Although there is data to be transmitted as described above, a situation in which data of another service cannot be transmitted due to transmission of a high priority service is referred to as 'starvation'. This 'Starvation' acts as a factor that significantly lowers the quality of service for a particular service. For example, in the case of a real-time service such as audio streaming, a certain amount of data must be continuously transmitted. If 'Starvation' occurs due to priority, packets that have not been transmitted for a long time are no longer needed. It is discarded and therefore the quality of service occurs.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide a method for efficiently allocating radio resources to each service in the case of providing a plurality of services in a wireless communication system. It is.

In one aspect of the present invention, a data delivery method according to the present invention, in the data transmission method for multiplexing a plurality of upper layer channels at the transmitting side of a wireless communication system (mapping) to a lower layer channel, Changing predetermined priorities of the plurality of upper layer channels according to whether at least one condition is satisfied, and converting each of the upper layer channel data by an amount determined according to the changed priorities to the lower layer channel. It can be configured to include multiplexing.

In another aspect of the present invention, a data transfer method according to the present invention is a data transfer method for multiplexing and mapping a plurality of higher layer channels to a lower layer channel at a transmitting side of a wireless communication system. Changing a predetermined priority for the at least one condition according to whether the at least one condition is satisfied, selecting a specific transmission format combination (TFC) from a set of specific transmission format combinations (TFCS) according to the changed priority; And transmitting each upper layer channel data to a lower layer according to the selected transmission format combination.

In another aspect of the present invention, a data delivery method according to the present invention is a data delivery method for multiplexing a plurality of service data at a transmitting side of a wireless communication system and mapping the same to a lower layer channel. And changing a preset priority according to whether at least one condition is satisfied, and multiplexing each service data by the amount determined according to the changed priority to the lower layer channel.

As another aspect of the present invention, a data transfer method according to the present invention, in a data transfer method for multiplexing a plurality of logical channels through a transport channel in the terminal of a mobile communication system to map to a coded transmission channel (CCTrCH) Changing a predetermined priority of the plurality of logical channels according to whether at least one condition is satisfied; and a specific transmission format combination (TFC) from among a set of preset transmission format combinations (TFCS) according to the changed priority. ), And transmitting each logical channel data to a lower layer according to the selected transmission format combination.

In another aspect of the present invention, the terminal for wireless communication according to the present invention, the process of changing the predetermined priority for a plurality of higher layer channels according to whether at least one or more conditions are satisfied, and according to the changed priority And selecting a specific transmission format combination (TFC) from among a set of transmission format combinations (TFCS) and delivering a higher layer channel data to a lower layer according to the selected transmission format combination.

Preferably, the preset priority and the at least one condition may be signaled from a base station. The changed priority may be maintained for a predetermined period. It is preferable that the priority of the upper layer channel whose priority is changed by the changed priority does not change for a predetermined period.

The at least one condition may be a condition regarding whether the amount of data stored in a buffer of any upper layer channel exceeds a predetermined threshold. At this time, when the amount of data stored in the buffer of any upper layer channel exceeds the predetermined threshold, the priority of the upper layer channel is adjusted upward.

The at least one condition may be a condition regarding whether an average waiting time of data stored in a buffer of any upper layer channel exceeds a predetermined reference value. In this case, when the average waiting time of data stored in the buffer of the arbitrary upper layer channel exceeds the predetermined reference value, the priority of the arbitrary upper layer channel is adjusted upward.

The upper layer channel may be a logical channel, and the lower layer channel may be a transport channel or a coded composite transport channel (CCTrCH).

Hereinafter, the structure, operation and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. Embodiments described below are examples in which technical features of the present invention are applied to a Universal Mobile Telecommunications System (UMTS) or an Evolved Universal Mobile Telecommunications System (E-UMTS).

1 is a diagram illustrating a network structure of an E-UMTS. The E-UMTS system evolved from the existing WCDMA UMTS system and is currently undergoing basic standardization work in the 3rd Generation Partnership Project (3GPP). E-UMTS is also called Long Term Evolution (LTE) system. The technical specifications of UMTS and E-UMTS are detailed in [http://www.3gpp.org/ftp/Specs/2006-12/] and [http://www.3gpp.org/ftp, respectively. /Specs/html-info/GanttChart-Level-2.htm].

Referring to FIG. 1, an E-UMTS is largely referred to as a user equipment (hereinafter abbreviated as UE), a base station (hereinafter referred to as an eNode B or eNB), and an access gateway connected to an external network at an end of a network (E-UTRAN). Access Gateway (hereinafter abbreviated as aGW). The aGW may be divided into a part that handles user traffic and a part that handles control traffic. In this case, a new interface can be used to communicate with each other between aGW for processing new user traffic and aGW for controlling traffic. One or more cells exist in one Node B. An interface for transmitting user traffic or control traffic may be used between the eNode Bs. The CN may be configured with aGW and a network node for user registration of the UE. An interface for distinguishing E-UTRAN and CN may be used. aGW manages mobility of UE in units of a tracking area (TA). The TA is composed of a plurality of cells, and when the UE moves from one TA to another TA, the TA informs the aGW that the TA where it is located has changed.

Layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) reference model, which is widely known in communication systems. L2 (second layer), L3 (third layer) can be divided into, wherein the physical layer belonging to the first layer provides an information transfer service (Information Transfer Service) using a physical channel, The radio resource control (hereinafter referred to as RRC) layer located in the third layer plays a role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the UE and the network. The RRC layer may be distributed to network nodes such as Node B and aGW, or may be located independently of Node B or aGW.

2 is a schematic diagram of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). In FIG. 2, the hatched portion shows the functional entities of the user plane and the unhatched portion shows the functional entities of the control plane.

3A and 3B illustrate a structure of a radio interface protocol between a UE and an E-UTRAN. FIG. 3A is a control plane protocol diagram and FIG. 3B is a user plane protocol diagram . The wireless interface protocol of FIGS. 3A and 3B horizontally consists of a physical layer, a data link layer, and a network layer, and vertically includes a user plane for data information transmission User Plane) and control plane (Control Plane) for transmitting control signal (Signaling). The protocol layers of FIG. 3A and FIG. 3B are classified into L1 (first layer), L2 (second layer), and L2 (third layer) based on the lower three layers of an Open System Interconnection L3 (third layer).

The physical layer as the first layer provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to a medium access control layer (upper layer) through a transport channel, and data between the medium access control layer and the physical layer moves through the transport channel. Data is transferred between the different physical layers, that is, between the transmitting side and the receiving side physical layer through the physical channel. In E-UMTS, the physical channel is modulated by an orthogonal frequency division multiplexing (OFDM) scheme, thereby utilizing time and frequency as radio resources.

The medium access control layer (hereinafter referred to as MAC) layer of the second layer provides a service to a radio link control layer, which is a higher layer, through a logical channel. The Radio Link Control (hereinafter referred to as RLC) layer of the second layer supports reliable data transmission. The PDCP layer of the second layer performs a header compression function to reduce unnecessary control information in order to efficiently transmit data transmitted using an IP packet such as IPv4 or IPv6 in a relatively low bandwidth wireless section. .

The radio resource control layer (hereinafter referred to as RRC) layer located at the bottom of the third layer is defined only in the control plane, and the configuration and resetting of the radio bearer (abbreviated as RB) are performed. It is responsible for the control of logical channels, transport channels and physical channels in relation to configuration and release. At this time, the RB means a service provided by the second layer for data transmission between the UE and the UTRAN.

Downlink transmission channels for transmitting data from the network to the UE include a broadcast channel (BCH) for transmitting system information, a paging channel (PCH) for transmitting a paging message, and a downlink shared channel (SCH) for transmitting user traffic or control messages. There is. In case of a traffic or control message of a downlink multicast or broadcast service, it may be transmitted through a downlink SCH, or may be transmitted via a separate downlink multicast channel (MCH). Meanwhile, the uplink transmission channel for transmitting data from the terminal to the network includes a random access channel (RAC) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or control messages.

A logical channel mapped to a transport channel is a broadcast channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), a multicast traffic channel ).

Hereinafter, a transport format combination (TFC) selection performed in the MAC layer of the UMTS system will be described.

TFC selection is a function of selecting a transport block (TB) and the number of the appropriate size according to the radio channel situation that changes momentarily, so that limited radio resources can be used as efficiently as possible. The MAC layer basically transmits transport blocks through the transport channel to the PHY layer. Transmission Block Set (TBS) means a set of transport blocks transmitted simultaneously through the same transport channel. In other words, the transport block set may be referred to as a set of transport blocks transmitted during a specific transmission time interval (TTI). TTI means a basic transmission time interval defined in a specific transmission channel, and has an integer multiple of 10 ms, which is a time unit called a radio frame. The transport block size is a value representing the size of a transport block in bits. A value representing the size of a transport block set in bits is called a transport block set size. The transport block size transmitted during a specific TTI in the same transport channel is always constant. Therefore, the transport block set size during a specific TTI has an integer multiple of the transport block size.

The transport format (TF) refers to configuration information of a transport block set transmitted during a specific TTI in one transport channel. The TF may be divided into dynamic configuration information and semi-static configuration information. The dynamic configuration information consists of transport block size and transport block set size information, and the static part consists of information such as TTI, error correction code, coding rate, rate matching parameter and CRC size. do. Transmit Format Set (TFS) means a set of TFs associated with a specific transport channel. The static part of all the TFs in the same TFS is the same. Since the transmission speed can be determined by the dynamic part of the TF, various transmission rates can be supported by changing the transport block size and the transport block aggregation size.

When determining the TF for a particular transport channel, the MAC layer must consider transport channel multiplexing in the PHY layer. Transport channel multiplexing is a mapping of multiple transport channels to one Coded Composite Transport Channel (CCTrCH). This function itself is performed at the PHY layer, but the MAC layer is mapped to the same CCTrCH at the time of TF determination. Consideration should be given to all transport channels. In fact, since the amount of data processed by the PHY layer is the amount transmitted through the CCTrCH, the MAC layer must determine the TF of each transport channel in consideration of the CCTrCH. At this time, the combination of the TFs is called a transport format combination (TFC).

 The TFC cannot be determined by the MAC layer itself, and must select one of the available TFC sets (TFCS: TFC Set) indicated by the RRC layer of the UTRAN. That is, the RRC layer of the UTRAN informs the MAC layer of the available TFCS for one CCTrCH during initial radio bearer (RB) configuration, and the MAC layer selects an appropriate TFC in the TFCS for every TTI. In the case of the terminal, the terminal RRC receives TFCS information wirelessly from the RRC of the UTRAN, and informs the MAC of the terminal.

The selection of the appropriate TFC for every TTI within a given TFCS is a function performed by the MAC layer, which consists of two steps. First, a valid TFCS is configured in the TFCS assigned to the CCTrCH, and then an optimal TFC is selected within the configured valid TFCS. The effective TFCS is a set of TFCs that can actually be used for the corresponding TTI among the given TFCSs because the radio channel situation changes every moment, and thus the maximum transmit power that the UE can transmit also changes. In general, the amount of data that can be transmitted is proportional to the size of the transmission power, so that the usable TFC is limited to the maximum transmission power.

The optimal TFC means a TFC capable of transmitting the maximum amount of data to be transmitted within the effective TFCS limited by the maximum transmit power. However, at this time, it is not necessary to select a TFC capable of transmitting a large amount of data unconditionally, and when selecting an optimal TFC within the effective TFCS, the logical channel priority is selected based on the logical channel priority. In the logical channel, the priority is set from 1 to 8 (1: highest priority). When multiple logical channels are multiplexed on one transport channel and multiple transport channels are multiplexed on one CCTrCH, the MAC layer is It is possible to select a TFC that can transmit the highest priority logical channel data.

4 is a process flow diagram of one preferred embodiment of the present invention. 4 illustrates an embodiment of a data processing method for multiplexing data related to a plurality of services in a terminal of a UMTS or an E-UMTS and transmitting the same to a network.

Referring to FIG. 4, the terminal receives control information related to the priority of the logical channel from the network (UTRAN or E-UTRAN) [S41]. The control information includes information related to a basic priority of a plurality of logical channels, at least one or more conditions for changing the basic priority, a method for changing the priority when a condition is satisfied, a period during which the changed priority is maintained, and the like. Since the terminal may transmit a plurality of services through a plurality of logical channels, the "priority of logical channels" may be replaced with the term "priority of services." The control information may be included in the system information when the system information is transmitted from the network to the terminal. As another example, the control information may be transmitted to the terminal when an RRC connection is established, a radio bearer (RB) is set up, changed or reset between the network and the terminal.

The terminal checks whether the at least one priority change condition included in the control information is satisfied every TTI [S42]. If the condition is satisfied, the basic priority included in the control information is changed according to the priority changing method [S43]. Hereinafter, the processes S41 to S43 of FIG. 4 will be described in more detail with reference to specific examples.

The terminal transmits RRC, Session Initiation Protocol (SIP), Voice of IP (VoIP), Best Effort (BE) 1, and BE2 services, and the basic priorities related to the services are RRC, SIP, VoIP, BE1, BE2. Suppose it is in order. In other words, RRC has the highest priority and BE2 has the lowest priority.

As described above, the network notifies the terminal of at least one condition in which the priority of the services is changed. One example of a condition for changing the priority may be the amount of data of each service stored in a Tx buffer of a logical channel. That is, when the amount of data stored in the transmission buffer for each service exceeds or exceeds a predetermined threshold, the priority of the corresponding service may be changed higher than the current priority.

For example, the network may be set to have a higher priority than BE1 when the amount of data of the BE2 service stored in the transmission buffer in the terminal exceeds 50 or more than the condition. That is, when the amount of data of BE2 stored in the transmission buffer exceeds 50, the priority of each service is changed in the order of RRC, SIP, VoIP, BE2, BE1. In addition to the priority change condition, the network may also inform the priority change method when the change condition is satisfied. For example, when BE2 satisfies the above priority change condition, it indicates how many times to change the priority. That is, for example, if it is set to change for the third time, the priority after the change is in the order of RRC, SIP, BE2, VoIP, BE1.

When the priority is changed, the network may inform the terminal how long to maintain the changed priority. For example, if the network sets the UE to maintain the changed priority for only 1 TTI, and the service of BE2 in the Nth TTI satisfies the priority change condition, the priority of each service in the Nth TTI Is changed from RRC, SIP, VoIP, BE1, BE2 to RRC, SIP, VoIP, BE2, BE1. Since the priority change holding period is 1 TTI, the next (N + 1) th TTI is changed back to RRC, SIP, VoIP, BE1, and BE2 which are basic priorities.

For a service whose priority has been changed once, it is also possible to set the priority not to change even if the condition for changing the priority is satisfied for a certain period of time. For example, if the BE2 service in the Nth TTI satisfies the priority change condition, the priority order of BE2 in the Nth TTI is changed. And, if the priority change holding period is 1 TTI, it will be changed back to the original priority in the (N + 1) th TTI. If, even in (N + 1) th TTI, the data of the BE2 service still exceeds the threshold, the terminal may not change the priority of the BE2 service.

For example, assuming that the network has set the prohibition of re-changing as 5 TTI and the change sustain period as 1 TTI, when the BE2 service satisfies the priority change condition at the Nth TTI, the changed priority is RRC, SIP. , Voip, be2, be1. In the (N + 1) th TTI, since the change maintenance period has passed, the original TN is changed to RRC, SIP, VoIP, BE1, and BE2. Further, even if the service of BE2 satisfies the priority change condition from the (N + 1) th TTI to the (N + 5 th TTI), the priority for the service is not changed because it is within 5 TTI, which is a priority change prohibition period. This is to avoid having a higher priority than the original priority if the amount of data in BE2 in the transmit buffer is very large.

The network may set one or more priority change conditions according to each service. For example, if the amount of data in the BE2 service exceeds 50, the priority change maintenance period is set to 1 TTI, and the priority change prohibition period is set to 5 TTI. 2 TTI, priority change prohibition period can be set to 4 TTI. Alternatively, if the data amount of the BE2 service exceeds 50, it may be changed to the fourth priority, and if the data amount exceeds 80, it may be changed to the third priority.

As another priority change condition, it is also possible to determine whether each service data waits in the transmission buffer for a predetermined reference value or more. For example, suppose the priority change condition of the BE2 service is whether the amount of data in the transmit buffer exceeds 50, the data in the BE2 service currently has 40 in the transmit buffer, and no more data from the BE2 service occurs. . When there is a large amount of data of RRC, SIP, VoIP and BE1 services having higher priority than the BE2 service, the 'starvation' phenomenon may continue because the BE2 service does not satisfy the priority change condition. In other words, in case of such a case, the network may set the average waiting time of data of each service to the terminal as a priority change condition. For example, when the network sets the priority change condition whether the average time for which the data of the BE2 service waits in the transmission buffer exceeds 10 TTI, the terminal determines the amount of time that the data of the BE2 service waits in the transmission buffer. Calculate the average value. The terminal changes the priority of the BE2 service by the above-described method when the average waiting time is more than 10 TTI.

The case where the priority change for each service is set based on the average waiting time of data in the transmission buffer will be described in more detail as follows. FIG. 5 is a diagram for describing a case of changing the priority based on the amount of data stored in the transmission buffer. In this case, it is assumed that the data of the BE2 service stored in the transmission buffer does not meet the priority change condition. In this case, even though data for BE2 service continues to delay transmission for an average of 10 TTIs, BE2's priority is not changed and thus 'starvation' of BE2 occurs.

FIG. 6 is a diagram for describing a method of changing priority when a priority change of each service is performed based on an average waiting time of data in a transmission buffer. In this case, assuming that the reference value of the average latency for changing the priority is 10 TTI, and the average latency waited for the data of the BE2 service in the transmission buffer is 10 TTI, the priority for each service is RRC, SIP, VoIP, BE2. , BE1 is changed, and data of BE2 is processed in preference to data of BE1. In other words, the method of setting the priority change condition as the average waiting time has a low amount of low priority data, and when the priority change condition is used as the data amount of the buffer, the priority change does not occur and the 'starvation' phenomenon still occurs. It is to prevent that.

There may be one or more conditions under which the priority for each service is changed. For example, as described above, if data of a specific service is accumulated in a transmission buffer by a predetermined amount, a condition in which the priority of the service is changed or the priority of the service is changed in addition to the condition is changed by a certain period of time. It may also include whether the average waiting time exceeds or exceeds a predetermined reference value. For example, the priority of the BE2 service may be changed according to the amount of data stored in the transmission buffer, and the priority may be changed according to the average latency of the data stored in the transmission buffer. It may be.

If the priority change condition is satisfied for two or more services at the same time, the priority may be changed using a sequential method. For example, suppose that the UE transmits three types of services BE1, BE2, and BE3, BE1 has the highest priority and BE3 has the lowest priority. If the priority change condition of BE2 and BE3 is satisfied at the same time in a specific TTI, the priority can be changed from the higher priority service. For example, if both of the priority change conditions of BE2 and BE3 are satisfied in the Nth TTI, the (N + 1) th TTI changes the priority in the order of BE2, BE1, and BE3. Assuming that the priority retention period is 1 TTI, the priority of BE2 returns to its original priority in the Nth TTI, and because the priority of BE3 in the Nth TTI has been postponed due to BE2's priority change, (N + In 1) th TTI, BE1, BE3, BE2 are set in order.

If other services also satisfy the priority change condition in the (N + 1) th TTI, the priority change is made in the (N + 1) th TTI. In the above examples, it is assumed that the priority level that is increased when changing the priority is one step, but may be increased to several levels according to the setting. For example, when the priority of BE3 is increased in two stages, it may be changed from BE1, BE2, BE3 to BE3, BE1, BE2. In this case as well, the priority change prohibition period may be set such that the priority change condition may not be changed even if the priority change condition is satisfied for a certain period after the change maintenance period.

When two or more services simultaneously satisfy the priority change condition, another way to change the priority is to change both services at once. For example, when BE2 and BE3 satisfy a priority change condition as described above at a specific TTI, the priority may be changed in order of BE2, BE3, BE1. Alternatively, if there are several priority change conditions for each service, the priority increase step of each service may be set differently. For example, if both BE2 and BE3 satisfy the priority change condition, and the data amount of BE2 stored in the transmission buffer is 50 and the data amount of BE3 is 100, the priority may be BE3, BE2, BE1. This method can be applied even when a service satisfies the priority change condition at one time. For example, if BE3 satisfies the priority change condition and the amount of BE3 service data in the buffer is 50, the priority is increased only in one step, and is set in the order of BE1, BE3, BE2. However, if the data amount is 100, the priority of the second stage may be increased so as to be BE3, BE1, BE2.

Referring back to FIG. 4, if the priority is changed, the terminal selects a specific TFC from the TFCS using the changed priority, and if not, using the default priority [S44]. The process of selecting a specific TFC in a given TFCS according to a logical channel or service priority will be described in more detail.

7 to 9 are diagrams for explaining a process of selecting a specific TFC in the TFCS received from the network by the MAC layer of the terminal according to an embodiment of the present invention. 7 is a flowchart illustrating a process of selecting a TFC according to the priority of a logical channel. FIG. 7 illustrates a case in which TrCH1 and TrCH2 which are transport channels are mapped to one CCTrCH, LoCH1 and LoCH2 which are logical channels are mapped to TrCH1, and LoCH3 is mapped to TrCH2. At this time, it is assumed that the priority of the logical channel is LoCH1 = 1, LoCH2 = 5, LoCH3 = 3, and LoCH1 has the highest priority. FIG. 9 illustrates a process of selecting a TFC according to the process of FIG. 7 in the example of FIG. 8.

In FIG. 8, the MAC layer selects an optimal TFC within a given TFCS for every TTI. The TFCS is as indicated in the box of FIG. 8, which is not determined by the MAC layer, but rather conveyed by the RRC layer to the MAC layer when establishing the RB. In the example of FIG. 8, a total of 16 TFCSs are defined. Each TFC has an identifier that identifies it, which is called the TFC Index (TFCI). When the MAC layer delivers transport block sets to the physical layer through each transport channel, the MAC layer indicates a related TFI value. The physical layer configures the TFCI using the transmitted TFI values. In the TFCS of FIG. 8, the number in parentheses originally means (the number of TBs in which the size of TrCH1 is Size1 and the number of TBs in which the size of TrCH2 is Size2). Here, it is assumed that all TBs have the same size (Size1, Size2) ( The number of TBs in TrCH1 and the number of TBs in TrCH2).

As shown in FIG. 8, it is assumed that Tx Buffer1 = 3, Tx Buffer2 = 4, and Tx Buffer3 = 2 data blocks are waiting to be transmitted in the TLC buffer of the RLC. Assume that you can transmit.

7 to 9, up to 10 TBs can be transmitted due to the limitation of the maximum transmission power among the total of 16 TFCS, and thus, a valid TFCS is configured except TFCI = 13 and 15 among the given TFCSs [S441]. .

Among the valid TFCSs configured in step S441, effective TFCSs excluding TFCs transmitting more TBs than the total number of TBs stored in the Tx buffer of the RLC for each transport channel are configured [S442]. The reason for excluding the TFC larger than the data amount of the transport channel is that if the TFC is selected, the radio resource is wasted because the RLC layer must generate and transmit a TB consisting of padding without any data. In the example of FIG. 8, since the data of TrCH1 is 7 TB by adding the data of LoCH1 and LoCH2, TFCI = 14 is excluded. Similarly, the data of TrCH2 is 2 TB, so TFCI = 9 and TFCI = 12 are excluded. This constitutes a new valid TFCS except TFCI = 9, 12, 14. Processes S441 and S442 may be reversed.

Since the logical channel having the highest priority is LoCH1 having P = 1, a new effective TFCS is configured based on LoCH1 [S443]. Since the data of LoCH1 is 3 TB, a new effective TFCS is configured by selecting TFCI = 6-11, which can transmit the most data of LoCH1 among the valid TFCSs configured in step S442 [S444].

Next, a new effective TFCS is constructed based on the high priority logical channel LoCH3. Since the data of LoCH3 is 2 TB, a new effective TFCS is configured by selecting TFCI = 8 and TFCI = 11 that can transmit the most data of LoCH3 among the newly configured valid TFCS. Next, a new valid TFCS is constructed based on the high priority LoCH3. Since the data of LoCH2 is 3 TB, a new effective TFCS is configured by selecting TFCI = 11 that can transmit the most data of LoCH2 among the newly configured valid TFCS. At this time, since there is only one TFC in the effective TFCS, this TFCI = 11 is selected as the optimal TFC. As a result, the number of TBs transmitted in this TTI becomes LoCH1 = 3, LoCH2 = 3, and LoCH3 = 2 for each logical channel [S443 ~ S446].

If the TFC is selected according to the priority [S44], the data of each logical layer (or service) is transferred to the lower layer according to the selected TFC [S45]. In the example of FIG. 8, TBs of LoCH1 = 3, LoCH2 = 3 and LoCH3 = 2 are delivered to the MAC layer according to the TFC of TFCI = 11, and LoCH1 and LoCH2 are multiplexed and mapped to TrCH1 in the MAC layer. LoCH3 is mapped to TrCH2 and data is delivered to the physical layer. In the physical layer, TrCH1 and TrCH2 are multiplexed to form a coded composite transport channel (CCTrCH) [S46]. Data multiplexed by CCTrCH is performed by the physical layer according to the protocol required data processing is transmitted to the network through the physical channel [S47].

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

According to the present invention, there is an effect of preventing waste of radio resources and efficiently using radio resources in a wireless communication system.

Claims (16)

A data transfer method for mapping a plurality of higher layer channels to a lower layer channel at a transmitting side of a wireless communication system, the method comprising: Changing predetermined priorities of the plurality of higher layer channels according to whether at least one condition is satisfied; And Multiplexing each higher layer channel data into the lower layer channel by an amount determined according to the changed priority; Wherein said at least one condition comprises a condition as to whether the amount of data stored in a buffer of any higher layer channel exceeds a predetermined threshold. The method of claim 1, And the preset priority is signaled from a base station. The method of claim 1, Wherein said at least one condition is signaled from a base station. The method of claim 1, The changed priority is maintained for a predetermined period of time, the data delivery method. 5. The method of claim 4, The priority of the higher layer channel whose priority is changed by the changed priority is not changed for a predetermined period. delete The method of claim 1, And if the amount of data stored in the buffer of any upper layer channel exceeds the predetermined threshold, the priority of the upper layer channel is adjusted upward. The method of claim 1, At least one condition comprises a condition as to whether the average latency of data stored in a buffer of any higher layer channel exceeds a predetermined reference value. 9. The method of claim 8, And if the average waiting time of data stored in the buffer of any upper layer channel exceeds the predetermined reference value, the priority of the upper layer channel is adjusted upward. The method of claim 1, Wherein the upper layer channel is a logical channel, and the lower layer channel is a transport channel or a coded complex transport channel (CCTrCH). A data transfer method for multiplexing a plurality of upper layer channels and mapping them to a lower layer channel at a transmitting side of a wireless communication system, Changing predetermined priorities of the plurality of higher layer channels according to whether at least one condition is satisfied; Selecting a specific transmission format combination (TFC) from a set of specific transmission format combinations (TFCS) according to the changed priority; And Delivering each upper layer channel data to a lower layer according to the selected transmission format combination; Wherein said at least one condition comprises a condition as to whether the amount of data stored in a buffer of any higher layer channel exceeds a predetermined threshold. 12. The method of claim 11, And said set of transmission format combinations is signaled from a base station. A data transfer method for multiplexing a plurality of service data on a transmitting side of a wireless communication system and mapping the same to a lower layer channel, Changing preset priorities for the plurality of services according to whether at least one condition is satisfied; And Multiplexing each service data in the lower layer channel by an amount determined according to the changed priority; Wherein said at least one condition comprises a condition as to whether the amount of data stored in a buffer of any higher layer channel exceeds a predetermined threshold. A data transfer method for multiplexing a plurality of logical channels through a transport channel in a terminal of a mobile communication system and mapping them to a coded complex transport channel (CCTrCH), Changing a predetermined priority of the plurality of logical channels according to whether at least one condition is satisfied; Selecting a specific transmission format combination (TFC) from a set of preset transmission format combinations (TFCS) according to the changed priority; And Delivering each logical channel data to a lower layer according to the selected transmission format combination; Wherein said at least one condition comprises a condition as to whether the amount of data stored in a buffer of any higher layer channel exceeds a predetermined threshold. Change a predetermined priority of a plurality of higher layer channels according to whether at least one condition is satisfied; Selecting a specific transmission format combination (TFC) from among a set of specific transmission format combinations (TFCS) according to the changed priority; A control unit configured to perform a process of transferring each upper layer channel data to a lower layer according to the selected transmission format combination; Wherein said at least one condition comprises a condition as to whether the amount of data stored in a buffer of any higher layer channel exceeds a predetermined threshold. A data transfer method for mapping a plurality of higher layer channels to a lower layer channel at a transmitting side of a wireless communication system, the method comprising: Changing predetermined priorities of the plurality of higher layer channels according to whether at least one condition is satisfied; And Multiplexing each higher layer channel data into the lower layer channel by an amount determined according to the changed priority; Wherein said at least one condition comprises a condition as to whether an average latency of data stored in a buffer of any higher layer channel exceeds a predetermined reference value.

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